Source

If you think you may have found a bug in XEmacs, please
read the Bugs section of the XEmacs manual for advice on
(1) how to tell when to report a bug, and
(2) how to write a useful bug report and what information
it needs to have.
There are three ways to read the Bugs section.
(1) In a printed copy of the XEmacs manual.
(2) With Info. Start XEmacs, do C-h i to enter Info,
then m XEmacs RET to get to the Emacs manual, then m Bugs RET
to get to the section on bugs. Or use standalone Info in
a like manner. (Standalone Info is part of the Texinfo distribution,
not part of the XEmacs distribution.)
(3) By hand. Do
cat info/xemacs* | more "+/^File: xemacs.info, Node: Bugs,"
Part II of the XEmacs FAQ, available in a manner similar to the above,
or via the world wide web, contains extensive information on how to
track down and report bugs.
http://www.xemacs.org/faq/